PartMet-Backup has been developed to prevent the loss of part.met-files after system-crashes or other ugly things that happen when using computers. If you lose those file or they get corrupted your ed2k-client will be unable to repeat the downloads. And as there are only few recovery-tools and even less are working fine you will certainly have to restart your download if anything bad happens to the part.met-files
PartMet-Backup helps you to secure the part.met-files. It backups the relevant files in regular intervals that you may customize. All this can be done automatically and it also takes care whether your ed2k-client is running at all, to be sure not to overwrite a valid backup with a corrupt one.